Electrosurgical systems are used by physicians to perform specific functions during surgical procedures. For example, in an ablation mode electrosurgical systems use high frequency electrical energy to remove soft tissue such as sinus tissue, adipose tissue or meniscus, cartilage and/or sinovial tissue in a joint. In a coagulation mode, the electrosurgical device may aid the surgeon in reducing internal bleeding by assisting in the coagulation and/or sealing of vessels.
The electrosurgical procedures are performed using high frequency signals, as such high frequency signals provide the desired electrosurgical effect and in theory should not result in muscle or nerve stimulation of the patient. Stated another way, unwanted muscle and nerve stimulation is induced by low frequency and/or direct current (DC) signals flowing across or through muscle or nerve. Equipment constructed in accordance with the International Electrotechnical Commission (IEC) standards use DC blocking capacitance between the voltage generator of the electrosurgical controller and the patient to block DC signals flowing to or from the voltage generator.
However, in spite of being constructed in accordance with IEC standards, muscle and/or nerve stimulation is still noted in some patients.